Physical Network Topology
Fault Description
Cannot get access to the public network.
Configuration Files
l AR
[V200R007C00SPCb00]
#
acl name Ethernet0/0/0 2998
rule 5 permit
acl name AllowNovum 2999
rule 5 permit source 103.0.0.0 0.255.255.255
#
traffic classifier VOICE operator or
if-match dscp ef
traffic classifier BEST_EFFORTS operator or
if-match dscp default
traffic classifier CONTROL operator or
if-match dscp cs7
traffic classifier SIGNALLING operator or
if-match dscp cs6
#
traffic behavior VOICE
queue ef bandwidth pct 10
traffic behavior BEST_EFFORTS
queue wfq
traffic behavior CONTROL
queue ef bandwidth pct 5
traffic behavior SIGNALLING
queue ef bandwidth pct 2
#
traffic policy qos_g_Ethernet0/0/0
classifier CONTROL behavior CONTROL
classifier SIGNALLING behavior SIGNALLING
classifier VOICE behavior VOICE
#
interface Cellular0/0/0
tcp adjust-mss 1200
dialer enable-circular
dialer-group 1
apn-profile mobile.vodafone.it
dialer timer autodial 20
dialer number *99# autodial
standby track nqa admin test
ip address negotiate
#
nqa test-instance admin test
test-type icmp
destination-address ipv4 127.0.0.1
frequency 5
probe-count 5
#
wlan ac
wmm-profile name default id 0
traffic-profile name default id 0
security-profile name default id 0
#
Troubleshooting Procedure
Step 1 Checking the status of LTE interface, run the display interface cellular 0/0/0 command to check the result.
Step 2 The LTE interface is down. By checking the configuration, there is a standby under the LTE interface and the NQA works fine, so the interface is down. After undo the standby command, interface becomes up.
But the interface still can’t get ip address
Run the display cellular 0/0/0 all to check the parameter of LTE :
Step 3 The current service is no services. We need make sure that the apn is right, and the sim card is not arrears. After change the apn, the interface can get ip address now.
But the lan users still can’t get access to the internet.
Step 4 Checking the route on AR, there's no default route. So packets will not be sent out correctly. And we should configure nat outbound under the LTE interface to make the packets can come back.
Root Cause
Configuration issue results the interface can't become up and can't get ip address.
It's because there's no nat and no default route which leads to the LAN users can't get accessible to the public network.
